President Trump on Wednesday denounced Sen. Dianne Feinstein for releasing the transcript of an interview of a key witness in the Senate Judiciary Committee’s investigation of Russian collusion with the Trump campaign — and in the process coined a new nickname for the California Democrat, the committee’s ranking minority member.

“The fact that Sneaky Dianne Feinstein, who has on numerous occasions stated that collusion between Trump/Russia has not been found, would release testimony in such an underhanded and possibly illegal way, totally without authorization, is a disgrace,” Trump tweeted on Wednesday morning, adding that he would like to see her face a primary challenge in 2018. “Must have tough Primary!”

The fact that Sneaky Dianne Feinstein, who has on numerous occasions stated that collusion between Trump/Russia has not been found, would release testimony in such an underhanded and possibly illegal way, totally without authorization, is a disgrace. Must have tough Primary!

On Tuesday, Feinstein’s office released the unclassified, 312-page transcript of the interview last August by Judiciary Committee staffers with Glenn Simpson, a founder of the research firm Fusion GPS, which was retained by the Clinton campaign to do opposition research on Trump.

Fusion hired Christopher Steele, a former British intelligence officer, who in turn produced the controversial dossier containing allegations of collusion with the Russian government, along with unsubstantiated claims about the Kremlin’s efforts to collect compromising information about Trump personally.

Congressional Republicans and the Trump campaign have tried to discredit the dossier as a partisan effort cooked up by the Clinton campaign. Although it contained no bombshells, Simpson’s testimony indicates that Steele was so troubled by what he found that he contacted the FBI to alert it to what he considered a possible crime.

The Republican chairman of the Judiciary Committee, Sen. Charles Grassley, has resisted calls to release the transcript, so Feinstein did it on her own.

Grassley called the release “disappointing” and his office put out a statement saying it “undermines the integrity of the committee’s oversight work and jeopardizes its ability to secure candid voluntary testimony.”

It is unclear what laws Feinstein might have broken or what Trump meant by calling the release “possibly illegal.” At around the same time as the documents went out to the public, Feinstein was one of a bipartisan group of legislators taking part in a cordial meeting with Trump to discuss immigration policy.

President Trump holds a bipartisan meeting with legislators on immigration reform at the White House on Tuesday. (Jonathan Ernst/Reuters)

In the interview, Simpson was asked if he had taken steps “assess the credibility” of the sources for Steele’s dossier, but he declined to discuss “sourcing information.” When pressed by the committee, Simpson’s lawyer Joshua Levy suggested it would be dangerous to do so.

“Somebody’s already been killed as a result of the publication of this dossier,” Levy said. “And no harm should come to anybody related to this honest work.”

“The single greatest Witch Hunt in American history continues,” the president tweeted. “There was no collusion, everybody including the Dems knows there was no collusion, & yet on and on it goes. Russia & the world is laughing at the stupidity they are witnessing. Republicans should finally take control!”

The single greatest Witch Hunt in American history continues. There was no collusion, everybody including the Dems knows there was no collusion, & yet on and on it goes. Russia & the world is laughing at the stupidity they are witnessing. Republicans should finally take control!

Feinstein has never ruled out the possibility of finding collusion between the campaign and Russians, although she said last month that Special Counsel Robert Mueller, who is overseeing a separate federal probe, seems to be focusing on building “a case of obstruction of justice” against Trump for his firing of FBI Director James Comey.

“It is my belief that that is directly because he did not agree to lift the cloud of the Russia investigation,” Feinstein said on NBC’s “Meet the Press” on Dec. 3. “That’s obstruction of justice.”